1. Industrial Field of the Invention
The present invention relates to a working device which can carry out a knurl-working to an armature shaft and can force the armature shaft into the through-hole of an armature core for a motor.
2. Related Art
Conventionally, an armature shaft has been attached to an armature core for a motor by forcing the armature shaft into the through-hole of the armature core after knurl-working of the armature shaft, in order to prevent rotation of the armature shaft with respect to the armature core. In this case, the step of the knurl-working is independent of the step of forcing the armature shaft into the through-hole of the armature core. The knurl worked armature shaft is supplied to an armature shaft forcing machine by the aid of human power after the direction of the armature shaft is correctly selected by the aid of human power. Thereafter, the armature shaft is forced into the through-hole of the armature core by means of the armature shaft forcing machine. Thus, the knurl-working for the armature shaft and the forcing of the armature shaft into the through-hole of the armature core are carried out by steps different from each other.
The knurl-working is carried out on the armature shaft asymmetrically with respect to the center of the length. That is, the knurl-working is carried out on the portion of the armature shaft except the portions in the vicinity of both ends thereof. Each of the non-knurl-working portions, in the vicinity of both ends of the armature shaft, has a different length to each other.
In order to force the armature shaft into the through-hole of the armature core, the so-called constant-length forcing system has been generally adopted. In this system, an armature shaft is forced into the through-hole of an armature core which is supported on the predetermined position, by a press machine having a hydraulic cylinder, to knock the armature shaft against a stopper fixed at a predetermined position. Consequently, the position of the armature shaft, relative to the armature core, can be determined.
The knurl-working is carried out on the portion of the armature so that each of the non-knurl-working portions in the vicinity of both ends of the armature shaft is different from each other, so that the armature shaft has a correct direction for forcing. However, the armature shaft has often been forced into the through-hole of an armature core in the wrong direction.
When various kinds of armature shafts are forced into the through-holes of armature cores, it is necessary to take account of the kind of armature shaft and the direction of the shaft. Therefore, the kind of armature shaft and the forcing direction of the shaft have been ascertained by the aid of human power. However, this determination not only requires a long time, but can also result in the possibility of making an incorrect ascertainment, with respect to the kind of armature shaft and the forcing direction of the shaft.